The present invention relates to a new schematic construction of electronic desk-top calculators essentially containing a display, a keyboard and a data processor unit, which has a combination of desirable features: compactness, light weight, productivity, economy and reliability.
Accordingly, it is an object of the present invention to provide electronic calculators which enable not only simplified construction of its individual components such as a display, a printed circuit board, a keyboard and a data processor unit, but also streamlined correlative arrangement of these components in order to attain compact and light weight construction and more particularly a low profile scheme.
It is another object of the present invention to provide improved calculators which carry electrical connections communicating between its individual components such as a display, a printed circuit board, a data processor unit, a battery, etc. and focused on a single point to thereby attain high degree of productivity.
It is still another object of the present invention to provide improved calculators wherein a cell or cells of liquid crystal are employed as a display and implementations of these liquid crystal cells are effectively combined with other components such as a circuit board, a keyboard, a data processor unit, a battery, etc.
With the aid of recent developments in the art of calculators, the individual components for example displays, data processor units, keyboards and power supplies are smaller and more closely and firmly united. For the displays, conventional NIXIE tubes and electroluminescent tubes of relatively large size have been replaced by miniature liquid crystal display cells. In addition, keyboards consisting of printed circuit boards and key actuators have been replaced by those employing folded flexible circuit films. See, for example, U.S. Pat. No. 3,911,234 issued on Oct. 7, 1975 and entitled KEYBOARD TYPE SWITCH ASSEMBLY HAVING FIXED AND MOVABLE CONTACTS DISPOSED ON FOLDABLE FLEXIBLE PRINTED CIRCUIT BOARD.
To meet the requirements that calculators be more compact and economical as stated above, the concept of the present invention is characterized by simplified constructions and effective organic arrangements of the individual components of electronic calculators, that is, the display, the printed circuit board, the keyboard, the data processor unit and the power supply.